Log points are different from breakpoints – they don’t break JS execution, they just create a log when hit.

It is now possible to copy all collected CSS changes done through DevTools UI. Thanks to Razvan Caliman!

Auto discovery of layout CSS properties (done by Micah Tigley). Hold shift and mouse over any defined property in the box-model widget (in the Layout sidebar). This will highlight the corresponding CSS property in the rule-view.

Layout Tools

Technical debt

Firefox 67 will soon display a removal notice (in the Options panel) about the Shader Editor, Canvas and Web Audio panels, which are going to be removed in 68. Work done by Yulia Startsev. Until the MDN page is up, you can look at the intent to unship post in the mailing list.

Performance tools

I/O markers are now visible in the timeline. I/O marker stacks are visible when hovering them, and in lots of cases the path of the file that was touched is shown.

When capturing a profile, to have I/O markers, you need to check the “Main Thread IO” checkbox in the Gecko profiler add-on, or enable the “mainthreadio” feature using the MOZ_PROFILER_STARTUP_FEATURES environment variable when profiling startup.

We are investigating optionally collecting markers for off-main thread I/O, and enabling main thread I/O markers by default.

A FileIO marker with operation, source, filename and stack information